Karak, S K and Chudoba, T and Witczak, Z and Lojkowski, W. and Manna, Indranil (2011) Development of ultra high strength nano-Y(2)O(3) dispersed ferritic steel by mechanical alloying and hot isostatic pressing. Materials Science and Engineering A - Structural Materials Properties Microstructure and Processing , 528 (25-26). pp. 7475-7483. ISSN 0921-5093

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Abstract

The present investigation aims to develop ultra high strength ferritic steels through consolidation of mechanically alloyed powders of 1.0 wt% nano-Y(2)O(3) dispersed 83.0Fe-13.5Cr-2.0Al-0.5Ti (alloy A), 79.0Fe-17.5Cr-2.0Al-0.5Ti (alloy B), 75.0Fe-21.5cr-2.0Al-0.5Ti (alloy C) and 71.0Fe-25.5Cr-2.0Al-0.5Ti (alloy D) alloys (all in wt%) by hot isostatic pressing (HIP) at 600.800 and 1000 degrees C using 1.2 GPa pressure for 1 h. Following this mechano-chemical synthesis and consolidation, extensive effort has been undertaken to characterize the microstructural evolution by X-ray diffraction, scanning and transmission electron microscopy and energy dispersive spectroscopy. Mechanical properties including hardness, compressive strength, Young's modulus and fracture toughness were determined using nano-indentation and universal testing machine. The present ferritic alloys record extraordinary levels of compressive strength (2012-3325 MPa), Young's modulus (230-295 GPa). fracture toughness (4.6-21.8 MPa root m) and hardness (15.5-193 GPa), and measure up to 2-3 time; greater strength with a lower density (similar to 7.4 Mg/m(3)) than that of other oxide dispersion strengthened ferritic steels (<1200 MPa) or tungsten based alloys (<2200 MPa). The novelty of these alloys lies in the unique microstructure comprising uniform dispersion of 20-30 nm Y(2)O(3) (ex situ) or Y(2)T(2)O(7) (in situ) particles in higher volume fraction in high-Cr ferritic matrix. (C) 2011 Elsevier B.V. All rights reserved.

Item Type:	Article
Uncontrolled Keywords:	Oxide dispersion strengthening; Ferritic steel; Mechanical alloying; Hot isostatic pressing; Mechanical properties
Subjects:	Processing Science
Divisions:	UNSPECIFIED
Depositing User:	Bidhan Chaudhuri
Date Deposited:	16 Jan 2012 12:12
Last Modified:	29 Mar 2012 12:53
URI:	http://cgcri.csircentral.net/id/eprint/270

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